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Discussion Starter #1
i bought a 94 mustang coupe a few days ago and drove it home which was about 12 miles. parked it in the drive way and the next day it wouldn't start. i thought it was the fuel pump so i took it out and ordered a new one, and then decided to test the pump so i hooked it to a battery and it works but it wont turn on when hooked up on the car. what could be wrong?
 

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Discussion Starter #3
where are those located i dont have the owners manual and theres a wire harness in the trunk that was cut theres alot of wires but its not conected to anything and it says remote keyless entry on the little box
 

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Did you check the fuel pump and ECM fuse in the engine bay fuse panel? Note, some ppl have reported that the ECM and FP fuses are labeled backwards. So check both of them.

Did you confirm +12 volts at the IFS shutoff switch in the trunk with the key on?

If there is power at the IFS shutoff switch, then the fuse and CCRM are good.

If no power at the IFS switch, test the CCRM and fuse.

Confirm power to the fuel pump before moving onto a possible ignition/PCM/ignition control module problem.
 

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Discussion Starter #5
well the was a mouse nest under the palenium, the fuse is good and i can pull my ignition out of the steering wheel but it works
 

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Did you test for power at the IFS switch?

Have you had a chance to look for damaged wires under the plenum? This is really going to determine how to attack this. For example, if the harness is basically intact, trouble shoot the issues as they come up.

If on the other hand there is extensive damage, it may be easier to replace the entire harness.
 

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Discussion Starter #7
no i havent taken the plenum off yet to look i was debating on taking out the drivers seat and plastic to fallow the harness all the way up and check for damaged wires and see that everything is together but i mean i drove it home then it quit working so im pretty confused on what it could be if it worked one day then not the next
 

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Discussion Starter #8
and i dont have a power tester or know what the IFS switch is but ill try posting some pix off what i got
 

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If you don't have a Volt-Ohm meter, then there's no sense in really doing anything. Inexpensive VOM meters can be had for $10 at any Autoparts store, Radio Shack, or Sears. Even Walmart would have something.

The inertia fuel shutoff switch (IFS) is a switch located in the trunk. It's job is to turn off the flow of fuel in the event of an accident. In many cars it's necessary to remove the trunk lining to get access to the terminals. The IFS swich is an easily accessible location to confirm power to the fuel pump.

IMO, the chances of anybody repairing a severely damaged wiring harness without a VOM meter are almost zero. This goes double for rodent damage. The loan exception would be obvious damage that can be spotted by visual inspection. The damage would have to be very limited. Rodent damage is a true crap shoot.

Even if you found the damage by visual inspection, how would you know the repair was effective? If multiple wires are involved, this would require you to trace down each wire and visually inspect. A truely daunting project.
 

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The red push button switch sure looks like the IFS switch to me.

The orientation of the switch is important. If not in the correct orientation it will trip too easily or take too much force.

You were looking for a reason why it worked and then didn't. Well there it is. The IFS is loose and free to bounce around inside the trunk. Likey you took a turn a little fast and it shifted. The impact with the inside of the trunk tripped it.

Try pressing the button to reset it and see if you now get power to the fuel pump.
 

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...remember the guy who tried starting his car with the copy of the key?
 

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...remember the guy who tried starting his car with the copy of the key?
If this is about the anti-theft (PATS) angle, remember the car is a 94 MY. Unless I'm mistaken, these cars didn't come with PATS.

At least that has been my thinking regarding the possible causes.

EDIT: well shoot. Looks like a 94 MY does have an anti-theft system (maybe an option). Will need to add this to a possible cause. However, don't the 98 and older PATS system disable the starter? This gives a no crank symptom.

I got the impression this is a crank with no-start.

In any case, does this car have a "chipped" key? What happens when the key is turned on but do not crank. Does the theft light go out after a 3 second "prove out"? Does the theft light blink during cranking? If so, STOP and find out why.

FWIIW, the cars older than 96 are somewhat out of my element. I don't normally work on pre-ODB2 cars. I generally don't answer posts on 95 and older cars because of a lack of reference material. However, I do have a new set of wiring diagrams that cover this model year. I thought I would put the new manuals to use on this thread.

Someone slap me back into my place. :nono:
 

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Discussion Starter #14
ok i got an ohms tester the fuse is good theres power to the switch (idk if its working) but theres no power to the plug in for the fuel pump ad no my key its a chip key it turns over and stuff and will start when the fuel pump problem is fixed but for some reason i can drive down the road and take the whole ignition out but im thinking fuel pump relay under the seat???
 

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Discussion Starter #15
well thanks for all the help after i put 400 dollars into it already you were right had to push the reset button in the trunk haha
 
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